The present disclosure relates generally to item handling, and particularly to collating devices.
Collating devices are used to collate flat items such as sheets, cards or envelopes, for instance to be further processed, for example to be folded and inserted into an envelope. Successful processing may require the items to be collected in a fashion having accurately controlled alignment of the items relative to one another and/or relative to a desired reference alignment.
In order to be able to collate and align items of different lengths, collating devices have employed various design features. U.S. Pat. No. 5,556,086 discloses a collating system using endless belts. A disadvantage of such system is the dependency of the collating result on the surface friction coefficients of the postal items (mutually and in interaction with the transporting means and stationary surfaces).
This disadvantage can be avoided using a system that is gripping each item during collation, as described in US patent application 2009/0250862A1 and US patent application 2010/0270125A1. The grippers are arranged for motion along a circulation path to carry items from an input area to a collection station. Such a collating system enables a relatively simple, compact and low cost solution for aligned collation of postal items of different sizes. However, while keeping the collating system relatively simple, transport velocity of the grippers along the circulation path (and thus processing throughput of the device) is limited because the items would be damaged or misaligned if the velocity at which the items are transferred to said collection station is too high.
Paper conveying machines are further known from DE 42 35 961 A1 and WO 2010/026647 A1.
US patent application US 2010/164162 A1 teaches to manually input a sheet size to be treated by an image forming apparatus in order to adjust a velocity of a discharge portion, comprising a belt with two grippers and discharge rollers. Further, a sensor detects the front end of a paper sheet being fed to a stacker, and based on the known length of the paper, the timing to change the velocity is determined.
In U.S. Pat. No. 4,678,172, a transport system for printed products is disclosed, wherein the speed can be varied in response to e.g. the press speed. The position of the printed products is detected by detection means for adjustment of speed for the conveyor belt.